1. Field of the Invention
The present invention relates to a fluid delivery system for a spray applicator that includes subsystems for filtering, heating and metered pumping of a fluid.
2. Background Art
Fluid delivery systems for spray applicators generally include a pump disposed in a chemical drum that supplies fluid to the spray applicator. Such systems may include flow meters for metering the supply of fluid. Other systems use backflow regulation to control the rate of flow to the spray applicator.
Some fluids such as in-mold coatings, adhesives and mold release agents pose problems for spray applicator systems due to the nature of the product being dispensed. For example, in-mold coatings that comprise pigmented coatings applied to a mold surface tend to accumulate in flow meters. Over time, the accuracy and effectiveness of flow meters degrades when used with in-mold coatings. Similarly, adhesives and mold release compounds tend to build up on internal surfaces of flow meters causing them to become clogged.
In-mold coatings and mold release compounds should be applied under controlled conditions in manufacturing operations to assure consistent molding results. The temperature at which such compounds are dispensed may materially affect performance and, in particular, the time required for such compositions to flash off. Flash off time, if not controlled, can lead to longer processing cycle times.
Foreign objects and impurities in chemicals that are to be dispensed with a spray applicator may interfere with spraying operations and may cause expensive spray guns and flow meters to become clogged or jammed.
There is a need for a fluid dispensing system for spray applicators that improves process control by permitting the material to be heated to an optimal temperature and also includes adequate filtration and a pumping system that accurately meters the quantity of fluid dispensed. There is also a need for such a system that is portable and may be easily connected and changed out on production spray applicator equipment.
These and other problems are addressed by applicants' invention as summarized below.